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The Basics: The Immune System and Cancer
The Immune System
THE BASICS: THE IMMUNE SYSTEM AND CANCER
Cancer cells can find every way to prevent the immune system from attacking them. Our immune system can function differently when cancer cells arrive. So how does the immune system work, and how does it mess up our body? Read on to find out.
The Immune System
Overview
The function of the immune system is to protect our bodies from diseases and infections. It identifies any foreign cells and will then send messages to other cells about an invading cell. Other cells will defend the body and destroy the foreign substances that can form an infection, such as microorganisms (bacteria, viruses, parasites, fungi). This is an immune response. An immune response is when the immune system recognizes a foreign cell and protects the body from any type of disease or infection.
T/B Cells
An immune response is accomplished with the help of lymphocytes, which are white blood cells. They are responsible for attacking bacteria, viruses, or any cells that invade the body. There are different types of lymphocytes, including T cells and B cells. The function of T cells is to eliminate damaged/infected cells and to notify B cells on when to produce antibodies. Antibodies are proteins that attack foreign cells by binding to the foreign substances, called antigens. A specific antibody can only bind to a specific antigen.
Non-Specific Immunity
Also known as innate immunity, it defends the body against harmful, foreign substances, such as viruses and bacteria. It is composed of cells and proteins that are prepared for any invaders and attack them when recognized. Examples of defenses are the skin and mucous membranes, which prevents the foreign cells from entering the body and causing infections. However, if they do pass the barriers, then phagocytes, which are white blood cells, will destroy the invading cells.
The infographic shows some of the nonspecific defenses that the body have to protect it from foreign substances. 1
Specific Immunity
Also known as the adaptive or acquired immunity, its job is to target a specific foreign cell, and it requires T and B cells to do so.
B cells produce antibodies, which are
proteins that are supposed to bind to an
antigen. An antigen is considered a foreign
substance. Antibodies are produced when
B cells mature and separates into plasma
cells. Nonetheless, T cells help notify
B cells on when they should mature and
produce antibodies. These antibodies will
then bind to a specific antigen. This
allows white blood cells to recognize the foreign substance and destroy it before it causes an infection.
Helper T cells’ functions are to initiate the B cells in separating into plasma cells, notify phagocytes to attack the foreign substances, and killer T cells will be initiated. This will allow the killer T cells to eliminate any infected cells in the body.
This shows how an antibody would attach to an antigen, and in this case, a tumor antigen. 2
How Infections Occur
When a pathogen enters the body and grows, an infection will develop. After, an immune response will occur, and the pathogen will be removed before diseases develop if the immune response is rapid. This will prevent diseases, since infections can cause certain diseases. However, diseases can appear when the body’s immunity is weakened, the pathogen is able to destruct host cells, or the pathogens are divided into a countless amount.
The Immune System With Cancer
The immune system does not function properly when there are cancer cells. The immune system fails to recognize cancer cells as foreign and does not attack them. Cancer cells have the ability to deactivate the immune response, which does not allow the immune system to attack the cancerous cells.
The immune system becomes less effective, since cancer and its treatments will weaken it. Chemotherapy or radiation can impact the bone marrow, which will affect the production of blood cells, since blood cells are developed in the bone marrow. When cancer treatments impact the bone marrow, the productivity of blood cells will lower. When the body lacks blood cells, it can not attack cancer cells effectively.
Watch this video to gain a further understanding of how the immune system functions when there are cancer cells in the body.
Normal Cell Cycle VS Cancer Cell Cycle
A normal cell would grow, copy its DNA, and divide when necessary. A cell will not divide if the DNA was not replicated correctly. In addition, it will not divide when its conditions are not favorable. For example, if the cell is accompanied by other cells, then it will not go through cell division. A normal cell would also experience apoptosis, which is when cells die, when needed. Contrary, cancer cells will continue to grow and divide in the presence of a mutation. Furthermore, they will grow when they are surrounded by other cells, unlike normal cells. This would cause tumors. Cancer cells will not undergo apoptosis, which allows them to continue dividing even in inappropriate surroundings, such as a genetic mutation. This would result in their daughter cells becoming more uncommon as they divide uncontrollably.
The infographic illustrates how a normal cell is different from cancer cells, regarding their cell divisions. 3